Amusement Park Forces What is a Force FORCE

Amusement Park Forces

What is a Force? FORCE = Any push or pull which causes something to move or change its speed or direction

Balanced Force 30 N The net force on an object is zero and the object’s motion does not change. Image: http: //image. wistatutor. com/content/force-laws-motion/balanced-force-example. jpeg; Definition: www. thefreedictionary. com

Unbalanced Force 50 N 20 N The net force of an object does not equal zero which results in a change in the motion of the object. Image: http: //image. wistatutor. com/content/force-laws-motion/unbalanced-force-example. jpeg; Definition: www. thefreedictionary. com

What is a Force? Forces can be BALANCED or UNBALANCED l l Balanced forces are equal in size and opposite in direction unbalanced forces are not equal in size and/or opposite in direction. If the forces on an object are UNBALANCED, we say a NET force results. Amusement Park Forces

What is a Force? Can you think of examples of forces? l Balanced Forces? l Unbalanced Forces?

Net Force The sum of all the forces acting on an object. (same direction=add, opposite directions= subtract) Image: http: //zonalandeducation. com/mstm/physics/mechanics/forces/net. Force/netf 3. gif; Definition: www. thefreedictionary. com

What is Motion? Motion: A change in position of an object compared to a reference point Motion involves all of the following:

Forces affect Motion: • • • They can make They can make direction. They can make objects objects start moving. move faster. move slower. stop moving. change objects change shape.

Gravity is a Force GRAVITY: GRAVITY An attraction force between all masses l Newton’s universal law of gravitation: gravitation Every object in the universe exerts a gravitational attraction to all other objects in the universe l The amount of gravitational force depends upon the mass of the objects and the distance between the objects

What is Friction? What are some ways athletes uses friction?

Friction is a Resistance Force Friction = A force that opposes or slows down motion l Caused by the physical contact between moving surfaces l The amount of friction depends upon the kinds of surfaces and the force pressing the surfaces together l Changes motion into heat

What is Motion? Speed The rate of change in position Speed = distance ÷ time or = distance time

What is Motion? Velocity Speed plus direction Example: 50 km/hour north

What is Motion? Acceleration The rate of change in velocity Positive acceleration = speeding up Negative acceleration = slowing down (decelerate) A change in the speed rate and/or direction, (velocity), of an object over time.

Acceleration by Brainpop 1) What units are used to measure speed? 2) What units are used to measure acceleration? 3) What is another way to say “slowing down” in terms of acceleration? 4) What units are used to measure velocity?

First Law(Law of Inertia): An object at rest stays at rest or an object in motion, stays in motion (in the same direction/at the same speed) unless acted upon by an unbalanced force

Inertia ü The tendency of an object to resist any change in its motion ü The greater the mass the greater the inertia ü The greater the speed the greater the inertia

Examples of Newton’s 1 st Law (do not copy) a) car suddenly stops and you strain against the seat belt b) when riding a horse, the horse suddenly stops and you fly over its head c) the magician pulls the tablecloth out from under a table full of dishes d) the difficulty of pushing a dead car e) lawn bowling on a cut and rolled lawn verses an uncut lawn f) car turns left and you appear to slide to the right

Examples of Newton’s 1 st Law of IInertia

Second law (Law of Force and Acceleration): ¡ ¡ The greater the force, the greater the acceleration The greater the mass, the greater the force needed for the same acceleration Calculated by: F = ma (F = force, m = mass, a = acceleration)

Examples of Newton’s 2 nd Law of Force and Acceleration (do not copy) a) hitting a baseball, the harder the hit, the faster the ball goes b) accelerating or decelerating a car c) The positioning of football players - massive players on the line with lighter (faster to accelerate) players in the backfield d) a loaded versus an unloaded truck

Examples of Newton’s 2 nd Law

Third law (Law of Action. Reaction): For every action force, there is an equal and opposite reaction force. (Forces are always paired)

Examples of Newton’s 3 rd Law (Do not copy) a) rockets leaving earth b) guns being fired c) two cars hit head on d) jumping out of a boat onto the dock

Examples of Newton’s 3 rd Law